Semiconductor Device Including Undulated Profile of Net Doping in a Drift Zone

ABSTRACT

A semiconductor device includes a semiconductor body having opposite first and second sides. The semiconductor device further includes a drift zone in the semiconductor body between the second side and a pn junction. A profile of net doping of the drift zone along at least 50% of a vertical extension of the drift zone between the first and second sides is undulated and includes doping peak values between 1×10 13  cm −3  and 5×10 14  cm −3 . A device blocking voltage V br  is defined by a breakdown voltage of the pn junction between the drift zone and a semiconductor region of opposite conductivity type that is electrically coupled to the first side of the semiconductor body.

BACKGROUND

Design of semiconductor devices such as power semiconductor devicesrequires trade-offs between electric characteristics such asarea-specific on-state resistance Ron×A, breakdown voltage Vbr betweenload terminals such as source and drain, switching behaviour and deviceruggedness.

By way of example, increasing a specific resistance of a bulk materialallows to achieve lower electric field strengths at a device front side.Although lower electric field strengths at the device front side mayimprove device ruggedness, a softness of the switching behaviour may beadversely affected.

It is desirable to improve the trade-off between electriccharacteristics in semiconductor devices.

SUMMARY

An embodiment refers to a semiconductor device comprising asemiconductor body having opposite first and second sides. Thesemiconductor device further comprises a drift zone in the semiconductorbody between the second side and a pn junction. A profile of net dopingof the drift zone along at least 50% of a vertical extension of thedrift zone between the first and second sides is undulated and includesdoping peak values between 1×10¹³ cm⁻³ and 5×10¹⁴ cm⁻³. A deviceblocking voltage V_(br) is defined by a breakdown voltage of the pnjunction between the drift zone and a semiconductor region of oppositeconductivity type that is electrically coupled to the first side of thesemiconductor body.

According to a method of manufacturing a semiconductor device, themethod comprises forming a profile of net doping in a drift zone of asemiconductor body by multiple irradiations with protons and generatinghydrogen-related donors and by annealing the semiconductor body. Atleast 50% of a vertical extension of the drift zone between first andsecond sides of the semiconductor body is undulated and includesmultiple doping peak values between 1×10¹³ cm⁻³ and 5×10¹⁴ cm⁻³. Themethod further comprises forming a semiconductor region at the firstside, wherein a device blocking voltage V_(br) is defined by a breakdownvoltage of a pn junction between the drift zone and the semiconductorregion.

Those skilled in the art will recognize additional features andadvantages upon reading the following detailed description and onviewing the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the disclosure and are incorporated in and constitute apart of this specification. The drawings illustrate the embodiments ofthe present disclosure and together with the description serve toexplain principles of the disclosure. Other embodiments and intendedadvantages will be readily appreciated as they become better understoodby reference to the following detailed description.

FIG. 1 is a schematic cross sectional view illustrating one embodimentof a semiconductor device.

FIG. 2 is a graph illustrating one embodiment of a net doping profile ofthe semiconductor device of FIG. 1.

FIG. 3 is a schematic cross sectional view illustrating one embodimentof a semiconductor device including p⁺-doped injection regions.

FIGS. 4A to 4D are schematic top views illustrating different layouts ofthe p⁺-doped injection regions of FIG. 3.

FIG. 5A is a graph illustrating one embodiment of a net doping profileof the semiconductor device of FIG. 3 and a reference device.

FIGS. 5B and 5C are graphs illustrating electric characteristics of thesemiconductor devices with net doping profiles as illustrated in FIG.5A.

FIGS. 6A and 6B are schematic cross sectional views illustratingembodiments of semiconductor diodes including buried p⁺-doped regions.

FIG. 7 is a schematic cross sectional view illustrating a semiconductordevice including hydrogen-related donors in a junction termination area.

FIG. 8 is a simplified chart illustrating process features of a methodof manufacturing a semiconductor device.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof, and in which are shownby way of illustrations specific embodiments in which the disclosure maybe practiced. It is to be understood that other embodiments may beutilized and structural or logical changes may be made without departingfrom the scope of the present invention. For example, featuresillustrated or described for one embodiment can be used on or inconjunction with other embodiments to yield yet a further embodiment. Itis intended that the present disclosure includes such modifications andvariations. The examples are described using specific language thatshould not be construed as limiting the scope of the appending claims.The drawings are not scaled and are for illustrative purposes only. Forclarity, the same elements have been designated by correspondingreferences in the different drawings if not stated otherwise.

The terms “having”, “containing”, “including”, “comprising” and the likeare open and the terms indicate the presence of stated structures,elements or features but not preclude the presence of additionalelements or features. The articles “a”, “an” and “the” are intended toinclude the plural as well as the singular, unless the context clearlyindicates otherwise.

The term “electrically connected” describes a permanent low-ohmicconnection between electrically connected elements, for example a directcontact between the concerned elements or a low-ohmic connection via ametal and/or highly doped semiconductor. The term “electrically coupled”includes that one or more intervening element(s) adapted for signaltransmission may exist between the electrically coupled elements, forexample elements that temporarily provide a low-ohmic connection in afirst state and a high-ohmic electric decoupling in a second state.

The Figures illustrate relative doping concentrations by indicating “−”or “+” next to the doping type “n” or “p”. For example, “n⁻” means adoping concentration that is lower than the doping concentration of an“n”-doping region while an “n⁺”-doping region has a higher dopingconcentration than an “n”-doping region. Doping regions of the samerelative doping concentration do not necessarily have the same absolutedoping concentration. For example, two different “n”-doping regions mayhave the same or different absolute doping concentrations.

FIG. 1 is a cross-sectional view of a part of a semiconductor device 100including a semiconductor body 105. The semiconductor body 105 mayinclude a semiconductor substrate, e.g. a silicon (Si) substrate, asilicon carbide (SiC) substrate or other single semiconductor orcompound semiconductor substrates including one or more optionalsemiconductor layers thereon. First and second sides 107, 108 of thesemiconductor body are opposite to each other.

A wiring area 110 is located at the first side 107 of the semiconductorbody 105. The wiring area 110 includes one or a plurality of wiringlevels, e.g. one or a plurality of patterned or non-patterned conductivelayers including one or a combination of conductive materials such asmetal(s), metal compound(s), silicide(s) and highly dopedsemiconductor(s). Different wiring levels or distinct parts of eachwiring level, e.g. distinct conductive lines are electrically isolatedby dielectric material(s), e.g. oxide(s) and/or nitride(s), diamond likecarbon (DLC). Openings in the dielectric material(s) may be filled withconductive material(s) and, together with the wiring level(s), provideelectric connection between different areas or device elements in thesemiconductor body 105 or between device element(s) in the semiconductorbody 105 and contact and/or bond pad(s).

According to one embodiment, the semiconductor device is a diodeincluding a p-doped anode region in a first area 112 at the first side107. The diode further includes an n⁺-doped cathode contact region in asecond area 113 at the second side 108. An optional n-doped field stopzone may be arranged in the second area 113 between the n⁺-doped cathodecontact region and the first area 112.

According to another embodiment, the semiconductor device is aninsulated gate bipolar transistor (IGBT) including a p-doped body regionand n⁺-doped source region of an IGBT emitter in the first area 112 atthe first side 107. The IGBT further includes a p⁺-doped region, e.g. aso-called p⁺-doped rear side emitter region in the second area 113 atthe second side 108. An optional n-doped field stop zone may be arrangedin the second area 113 between the p⁺-doped region and the first area112.

The semiconductor device 100 further includes an n-doped drift zone 114between the first and second areas 112, 113. A device blocking voltageV_(br) is defined by a breakdown voltage of a pn junction between thedrift zone 114 and a semiconductor region of opposite conductivity typein the first area 112 that is electrically coupled to the wiring area110 at first side 107 of the semiconductor body 105. A profile of netdoping of the drift zone 114 along at least 50% or even more than 70% ofa vertical extension t of the drift zone 114 between the first andsecond sides 107, 108 is undulated and includes several doping peakvalues between 1×10¹³ cm⁻³ and 5×10¹⁴ cm⁻³. Typically, more than threeor even more than five doping peaks are realized by multiple protonirradiations.

According to an embodiment, the undulated profile of net doping in thedrift zone 114 includes hydrogen-related donors. Doping withhydrogen-related donors may be effected by irradiating the semiconductorbody 105 with protons, e.g. through the second side 108 and/or throughthe first side 107 and annealing of the semiconductor body 105. Thereby,formation of complexes comprising hydrogen atoms and theirradiation-induced defects like e.g. vacancies results in the creationof donors, i.e. so-called hydrogen-related donors in this region.

According to an embodiment, a profile of the hydrogen-related donorsoverlaps with a p-doping in the first area 112. According to anembodiment, the profile of the hydrogen-related donors overlaps with ap-doped anode region of a diode. According to yet another embodiment,the profile of the hydrogen-related donors overlaps with a p-doped bodyregion of an IGBT or field effect transistor (FET). Thereby, a netdoping around the pn junction between the drift zone 114 and the firstarea 112 may be reduced below a basic doping of the semiconductor body,e.g. below the basic doping set during wafer growth of a raw material,e.g. a semiconductor wafer such as a silicon wafer or a silicon carbidewafer. This allows to reduce a thickness of the semiconductor body 105of the semiconductor device 100 for a given breakdown voltage, and,hence, to reduce electric losses. Furthermore, this allows to reduce anelectric field strength around the pn junction at the first side 107.Thereby, the ruggedness of the semiconductor device 100 with respect toswitching and/or cosmic radiation may be improved.

According to an embodiment, the undulated profile of net doping of thesemiconductor device 100 includes at least two minima, or at least threeminima or even at least five minima and a doping concentration of the atleast two minima decreases from the second side 108 to the first side107.

According to another embodiment of the semiconductor device 100, anaveraged profile of the net doping in a depth d of the drift zone 114with respect to the first side 107 is a net doping value averaged in adepth range d±0.1*t, t being a vertical extension of the drift zonebetween the first and second sides, and the averaged profile of netdoping increases with respect to at least 20%, or even more than 30% oreven more than 50% or even more than 70% of the vertical extension t ofthe drift zone 114 from the first side 107 to the second side 108.

The above profiles of net doping may be formed by multiple irradiationswith protons at different energies and/or doses and/or annealingprocesses. According to an embodiment, the annealing is carried out in atemperature range of 300° C. and 500° C. for a duration between one tofour hours. According to another embodiment, the annealing is carriedout in a temperature range of 350° C. and 430° C. for a duration betweenone to four hours.

The above profiles of net doping in the drift zone 114 include a ratherlow doping concentration around the pn junction between the drift zone114 and the first area 112 and the average profile increases from adoping concentration around or below the basic doping of thesemiconductor body at the pn junction through the drift zone 114 towardsa higher average doping concentration of an optional field stop zone inthe second area 113. An undulation of the net doping profile may beadjusted by appropriately choosing proton irradiation parameters such asnumber, energy, and/or dose of proton irradiation, e.g. protonimplantation and annealing parameters such as annealing temperature andannealing duration.

In a vertical range between a center of the drift zone 114 and an end ofthe drift zone 114 with respect to the second side 108, the net dopingprofile according to the above embodiments serves as an area forreduction of the electric field strength, e.g. as a field stop region,thereby improving the softness of the switching behavior. In a verticalrange of the drift zone 114 close to the pn junction between the driftzone 114 and the first area 112, the net doping profile according to theabove embodiments serves as an effective measure for reducing the netdoping below the basic doping of the semiconductor body 105, whichallows for a local reduction of the electric field strength. The localreduction of the electric field strength close to the pn junctionbetween the drift zone 114 and the first area 112 allows to improve theruggedness of the semiconductor device 100 and to reduce a thickness ofthe semiconductor device 100 resulting in a reduction of electriclosses.

FIG. 2 is a graph illustrating a net doping/carrier concentration c_(m)versus a vertical extension along a depth d of a semiconductor diode.The illustrated net doping profile is one embodiment of a net dopingprofile along a line A-A′ of the semiconductor device 100 illustrated inFIG. 1.

The illustrated net doping profile has been measured by spreadingresistance profiling (SRP), also known as spreading resistance analysis(SRA), which is a technique used to analyze resistivity versus depth insemiconductors. The basic doping of the semiconductor body of thesemiconductor diode, i.e. the basic doping of the raw material used tofabricate the semiconductor diode is indicated in the graph as ahorizontal line denoted as c_(r).

The semiconductor diode includes a field stop zone in the second area113 between the drift zone 114 and the second side 108 located in thedepth range between approximately 3 μm and 10 μm. The field stop zoneincludes a doping peak profile p_(f) decreasing to the first and secondsides 107, 108. The doping peak profile p_(f) may result fromhydrogen-related donors formed by proton irradiation and annealing, forexample.

An n⁺-doped cathode contact region is located between the field stopzone and the second side 108. The n⁺-doped cathode contact regionincludes the part of the illustrated net doping profile in the depthrange between approximately 0 μm and 3 μm.

A p-doped anode region is located in the first area 112 in the depthrange starting from approximately 82 μm. The p-doped anode region may beformed by introducing p-type dopants, e.g. one or any combination ofboron (B), indium (In), aluminum (Al), gallium (Ga), for example. Thep-type dopants may be introduced by ion implantation and/or a diffusionprocess, for example.

According to the illustrated embodiment, the profile of net doping c_(m)in the drift zone 114 is undulated along at least 50% of the verticalextension t of the drift zone 114 between the first and second sides107, 108 and includes doping peak values between 1×10¹³ cm⁻³ and 5×10¹⁴cm⁻³. The drift zone 114 is located between approximately 10 μm and 83μm.

The dimensions described with respect to FIG. 2 are merely examples andmay differ in other embodiments.

According to the illustrated embodiment, the profile of net doping c_(m)includes at least two minima, and a doping concentration of the at leasttwo minima decreases from the second side to the first side, cf.illustrated minima denoted m₁, m₂, m₃.

According to the illustrated embodiment, a full width at half maximum(FWHM) of net doping peaks of the drift zone 114 increases from thesecond side 108 to the first side 107, cf. illustrated full widths athalf maximum denoted FWHM₁, FWHM₂, FWHM₃. The net doping profileaccording to the illustrated embodiment may be formed by irradiating thesemiconductor body 105 from the second side 108. The irradiation orimplantation energy of the protons related to the FWHM₁ is larger thanthe irradiation or implantation energy of the protons related to theFWHM₂, FWHM₃. Likewise, the irradiation or implantation energy of theprotons related to the FWHM₂ is larger than the irradiation orimplantation energy of the protons related to FWHM₃. Since largerirradiation energies result in an increased width of the so-calledend-of-range peak, the different implantation energies result in theillustrated profiles denoted FWHM₁, FWHM₂, FWHM₃.

In the embodiment illustrated in FIG. 2, the net doping profile in thedepth range between approximately 10 μm and 50 μm is beneficial withrespect to soft switching behavior, whereas the net doping profile inthe depth range between approximately 52 μm and 58 μm as well as between65 μm and 80 μm has concentration values smaller than a basic doping ofthe raw material, e.g. due to compensation doping caused by crystaldamage due to irradiation. The basic doping may be defined by dopants ofthe raw material before undergoing front-end processing, e.g. by group Vimpurities such as phosphorus (P), arsenic (As), antimony (Sb) in ann-doped raw material. As an example of doping the raw materialmanufactured by Czochralski (CZ) growth, dopants may be introduced intoa silicon melt from where a silicon ingot is pulled. Lowering of the netdoping below the basic doping of the raw material allows for a localreduction of the electric field strength close to the pn junctionbetween the drift zone 114 and the first area 112, and thus allows toimprove the ruggedness of the semiconductor device 100 and to reduce athickness of the semiconductor device 100 resulting in a reduction ofelectric losses.

The net doping profiles according to the embodiments allow for animproved trade-off between electric characteristics.

FIG. 3 is a cross-sectional view of a part of a semiconductor diode 101according to an embodiment. The semiconductor diode includes a p-dopedanode region in the first area 112. The semiconductor diode 101 includesthe drift zone 114 as described in detail with respect to the embodimentillustrated in FIG. 1.

According to the embodiment illustrated in FIG. 3, the semiconductordiode 101 further comprises p⁺-doped and n⁺-doped areas 120, 121alternatingly arranged along a lateral direction×parallel to the secondside and electrically connected to an electrode 124 at the second side.

The n⁺-doped areas 121 of the semiconductor diode 101 constitute cathodecontact regions.

The p⁺-doped areas 120 of the semiconductor diode 101 constitute socalled p-short regions configured to inject holes from the second side108 during switching operations of the semiconductor diode 101. Apenetration depth of the p⁺-doped areas 120 may be approximately thesame as the penetration depths of the n⁺-doped areas 121 oralternatively may be smaller, which means that they are embedded in then⁺-doped areas 121.

The p⁺-doped areas 120 may be arranged in a vast variety of ways withrespect to the n⁺-doped areas 121. Typical designs are illustrated astop views in FIGS. 4A to 4D and include, inter alia, polygonal p⁺-dopedareas 120 (FIG. 4A), square p⁺-doped areas 120 (FIG. 4B), circularp⁺-doped areas 120 (FIG. 4C), and stripe-shaped p⁺-doped areas 120 (FIG.4D). Other typical designs include elliptic p⁺-doped areas 120,triangular p⁺-doped areas 120, crosswise00000, p⁺-doped areas 120 andany combination of the above shapes.

The semiconductor diode of the embodiments illustrated in FIGS. 3 to 4Dallows for a soft switching behavior in combination with reducedswitching losses. By adjusting the net doping profile in the drift zone114 a dynamic of electric field buildup during a turn-off period as wellas a hole injection by the p⁺-doped areas 120 may be appropriately setto achieve a soft switching nearly independent of current, voltage andswitching speed. Furthermore, hole injection by the p⁺-doped areas 120at undesirable times during switching may be reduced leading to acombined improvement of the switching behavior and electric losses. Thep⁺-doped areas 120 also improve a breakdown voltage stability ofsemiconductor diodes.

FIG. 5A is a graph illustrating a net doping/carrier concentrationc_(ms) versus a vertical extension along a depth d of a semiconductordiode according to an embodiment. The illustrated net doping profilec_(ms) is another embodiment of a net doping profile along a line A-A′of the semiconductor device 100 illustrated in FIG. 1.

The net doping profile c_(ms) is associated with the semiconductor diodeincluding an undulated net doping profile in the drift zone 114 withdoping peak values between 1×10¹³ cm⁻³ and 5×10¹⁴ cm⁻³. Furthermore, thesemiconductor diode includes p⁺-doped and n⁺-doped areas 120, 121alternatingly arranged along a lateral direction×parallel to the secondside and electrically connected to the electrode 124 at the second side,cf. FIG. 3.

A reference semiconductor diode includes a net doping profile c_(r) thatdiffers from the net doping profile c_(ms) with respect to the profilein the drift zone 114. The net doping profile c_(r) of the referencesemiconductor diode is almost constant in the drift zone 114. Similar tothe semiconductor diode including the net doping profile c_(ms), thereference semiconductor also includes p⁺-doped and n⁺-doped areas 120,121 alternatingly arranged along a lateral direction×parallel to thesecond side.

Similar to the graph illustrated in FIG. 2, the net doping profilesc_(ms), c_(r) have been measured by spreading resistance profiling(SRP), also known as spreading resistance analysis (SRA).

FIG. 5B is a graph illustrating a timing of a diode voltage during diodecommutation of the semiconductor diode including the net doping profilec_(ms) of FIG. 5A (left part of graph of FIG. 5B) and the referencesemiconductor diode including the net doping profile c_(r) of FIG. 5A(right part of graph of FIG. 5B) for different intermediate circuitvoltages. The semiconductor diode including the net doping profilec_(ms) is superior to the reference semiconductor diode including thenet doping profile c_(r) with respect to undesirable voltage overshoots.

FIG. 5C is a graph illustrating a trade-off between losses in switchingand conducting mode for semiconductor diodes including a net dopingprofile similar to c_(ms) of FIG. 5A (group denoted A) and referencesemiconductor diodes including a net doping profile similar to the netdoping profile c_(r) of FIG. 5A (group denoted B). The graph illustratesa switching loss identified by a reverse recovery energy normalized bythe current E_(rec)/A (versus a forward voltage Vf at a referencecurrent. The semiconductor diodes including the net doping profilesimilar to c_(ms) provide the benefit of smaller switching lossescompared with the reference semiconductor diodes including a net dopingprofile similar to c_(r).

FIGS. 6A, 6B are cross-sectional views of a part of semiconductor diodes102, 103 according to other embodiments. The semiconductor diodes 102,103 are similar to the semiconductor device 100 illustrated in FIG. 1and further comprise p-doped regions 127 buried in the semiconductorbody 105 at the second side 108 and embedded in n-doped semiconductormaterial of the semiconductor body 105.

With respect to the semiconductor diode 102 illustrated in FIG. 6A, thep-doped regions 127 are surrounded by n⁻-doped semiconductor material ofthe drift zone 114 and the cathode contact region 124. With respect tothe semiconductor diode 102 illustrated in FIG. 6A, the p-doped regions127 are surrounded by n-doped semiconductor materials of the drift zone114 and the cathode contact region 124, respectively. With respect tothe semiconductor diode 103 illustrated in FIG. 6B, the p-doped regions127 are surrounded by n-doped semiconductor materials of a field stopzone 128 and the cathode contact region 124, respectively.

The p-doped regions 127 are beneficial with respect to stabilizingdynamic avalanche during switching.

The p-doped regions 127 may also be applied to the an IGBT having abasic structure as illustrated in FIG. 1. In this case, the p-dopedregions 127 may be surrounded by an n-doped field stop zone, forexample.

According to another embodiment illustrated in FIG. 7, a semiconductordevice 104 includes the first and second areas 112, 114 similar to thesemiconductor device 100 illustrated in FIG. 1. Further, thesemiconductor device 104 includes, apart from an undulated net dopingprofile in the drift zone 114, hydrogen-related donors in addition tothe basic doping of the raw material of the semiconductor body 105 in aportion 133 of a junction termination area 131 between the pn junctionand the first side 107. The hydrogen-related donors may improve areliability of the junction termination.

FIG. 8 is a simplified chart illustrating process features of a methodof manufacturing a semiconductor device.

Process feature 5100 includes forming a profile of net doping in a driftzone of a semiconductor body by multiple irradiations with protons andgenerating hydrogen-related donors by annealing the semiconductor body,wherein at least 50% of a vertical extension of the drift zone betweenfirst and second sides of the semiconductor body is undulated andincludes multiple doping peak values between 1×10¹³ cm⁻³ and 5×10¹⁴cm⁻³. Typically, at least two or more than three or even more than fivedoping peaks are realized multiple proton irradiations, e.g. at leasttwo or more than three or even more than five proton irradiations.

Process feature S110 includes forming a semiconductor region at thefirst side, wherein a device blocking voltage V_(br) is defined by abreakdown voltage of a pn junction between the drift zone and thesemiconductor region.

According to an embodiment, the annealing is carried out in atemperature range of 300° C. and 500° C. for a duration between one tofour hours. According to another embodiment, the annealing is carriedout in a temperature range of 350° C. and 430° C. for a duration betweenone to four hours.

In another embodiment, the irradiation with protons is carried out fromthe second side.

Yet another embodiment further comprises forming distinct p⁺-dopedregions at the second sides, and forming a continuous n⁺-regionlaterally surrounding the distinct p⁺-doped regions at the second side.

Another embodiment further comprises forming p-doped regions buried inthe semiconductor body at the second side and embedded in n-dopedsemiconductor material of the semiconductor body.

According to another embodiment, the annealing is carried out atdifferent temperatures with respect to at least some of the protonirradiations. Annealing at lower temperatures, e.g. around 350° C. orbelow allows to form regions acting as doped regions and recombinationregions.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat a variety of alternate and/or equivalent implementations may besubstituted for the specific embodiments shown and described withoutdeparting from the scope of the present invention. By way of example,the semiconductor regions denoted p-doped or n-doped in the illustratedembodiments may also be doped vice versa, i.e. the semiconductor regionsdenoted p-doped may be n-doped and the semiconductor regions denotedn-doped may be p-doped. This application is intended to cover anyadaptations or variations of the specific embodiments discussed herein.Therefore, it is intended that this invention be limited only by theclaims and the equivalents thereof.

What is claimed is:
 1. A semiconductor device, comprising: asemiconductor body having opposite first and second sides; and a driftzone in the semiconductor body between the second side and a pnjunction, wherein a profile of net doping of the drift zone along atleast 50% of a vertical extension of the drift zone between the firstand second sides is undulated and includes multiple doping peak valuesbetween 1×10¹³ cm⁻³ and 5×10¹⁴ cm⁻³, wherein a device blocking voltageV_(br) is defined by a breakdown voltage of a pn junction between thedrift zone and a semiconductor region of opposite conductivity type thatis electrically coupled to the first side of the semiconductor body. 2.The semiconductor device of claim 1, wherein the undulated profile ofnet doping includes hydrogen-related donors.
 3. The semiconductor deviceof claim 1, wherein the undulated profile of net doping includes atleast two minima, and a doping concentration of the at least two minimadecreases from the second side to the first side.
 4. The semiconductordevice of claim 1, wherein the undulated profile of net doping includesat least three minima, and a doping concentration of the at least threeminima decreases from the second side to the first side.
 5. Thesemiconductor device of claim 1, wherein the undulated profile of netdoping includes a field stop zone adjoining an n⁺-doped contact region,and the field stop zone includes a doping peak profile decreasing to thefirst and second sides, respectively.
 6. The semiconductor device ofclaim 1, wherein an averaged profile of net doping in a depth d of thedrift zone with respect to the first side is a net doping value averagedin a depth range d±0.1*t, t being a vertical extension of the drift zonebetween the first and second sides, and the averaged profile of netdoping increases with respect to at least 50% of the vertical extensionof the drift zone from the first to the second side.
 7. Thesemiconductor device of claim 1, wherein the profile of net doping ofthe drift zone includes at least one peak in a depth range0.45*Δ<d<0.55*Δ, d being a vertical distance with respect to the firstside of the semiconductor body and Δ being a thickness of thesemiconductor body between the first and second sides.
 8. Thesemiconductor device of claim 7, further comprising a field stop zonebetween the drift zone and the second side.
 9. The semiconductor deviceof claim 1, wherein a full width at half maximum of net doping peaks ofthe drift zone increases from the second side to the first side.
 10. Thesemiconductor device of claim 1, further comprising, in a junctiontermination area, hydrogen-related donors between the pn junction andthe first side.
 11. The semiconductor device of claim 1, furthercomprising p⁺-doped and n⁺-doped areas alternatingly arranged along alateral direction parallel to the second side and electrically connectedto an electrode at the second side.
 12. The semiconductor device ofclaim 11, wherein the p⁺-areas are distinct p⁺-regions laterallysurrounded by a continuous n⁺-region including the n⁺-areas.
 13. Thesemiconductor device of claim 1, further comprising p-doped regionsburied in the semiconductor body at the second side and embedded inn-doped semiconductor material of the semiconductor body.
 14. Thesemiconductor device of claim 1, wherein the semiconductor device is adiode and the semiconductor region is an anode region.
 15. Thesemiconductor device of claim 1, wherein the semiconductor device is aninsulated gate bipolar transistor and the semiconductor region is a bodyregion electrically coupled to an emitter terminal of the insulated gatebipolar transistor.
 16. The semiconductor device of claim 1, wherein anet doping concentration of a part of the drift zone is smaller than adoping concentration of a raw material of the semiconductor body.
 17. Amethod of manufacturing a semiconductor device, the method comprising:forming a profile of net doping in a drift zone of a semiconductor bodyby multiple irradiations with protons and generating hydrogen-relateddonors by annealing the semiconductor body, wherein at least 50% of avertical extension of the drift zone between first and second sides ofthe semiconductor body is undulated and includes multiple doping peakvalues between 1×10¹³ cm⁻³ and 5×10¹⁴ cm⁻³; and forming a semiconductorregion at the first side, wherein a device blocking voltage V_(br) isdefined by a breakdown voltage of a pn junction between the drift zoneand the semiconductor region.
 18. The method of claim 17, wherein theannealing is carried out in a temperature range of 300° C. and 500° C.for a duration between one to four hours.
 19. The method of claim 17,wherein the annealing is carried out in a temperature range of 350° C.and 430° C. for a duration between one to four hours.
 20. The method ofclaim 17, wherein the multiple irradiations with protons is carried outfrom the second side.
 21. The method of claim 17, further comprisingforming distinct p⁺-doped regions at the second sides, and forming acontinuous n⁺-region laterally surrounding the distinct p⁺-doped regionsat the second side.
 22. The method of claim 17, further comprisingforming p-doped regions buried in the semiconductor body at the secondside and embedded in n-doped semiconductor material of the semiconductorbody.